Gandalf Supermodem : Java Glossary

Gandalf, a Canadian company, was the first to produce a 9600
BPS (Bits Per Second)
modem that could work on dial-up phone lines. The modem contained more computing
horsepower than most modern computers. It worked by playing chords of tones for 1/40
second. Averaging the signal over such a long time eliminated most of the effects of
static. At the receiving end, Fast Fourier transforms analysed the chords back into
the component tones. Most modern high speed modems have started with this idea and
refined it. The ingenuity of modern modems such as the Telebit Trailblazer is
extraordinary. The only problem is, all these schemes are proprietary, so different
brands of modems cannot talk to each other.